AragoniteCaCO3

Aragonite, a member of the aragonite group, is extremely rare at MSH.

PHYSICAL CHARACTERISTICS:

Color varies from colorless to white and pinkish yellow.Luster is vitreous to resinous.Diaphaneity is transparent to translucent.Crystal System is orthorhombic; Pmcn.Crystal Habits include aggregates of tabular crystals to 7mm; and . as cleavage fragments.Cleavage: {010} is distinct and {110} is indistinct.Fracture is subconchoidal.Hardness is 3.5 - 4.Specific Gravity is approximately 2.95 g/cm3.Streak is colorless.Associated Minerals include analcime, calcite, dolomite, natrolite, polylithionite, pyrite and siderite.Distinguishing Features: Crystal habit.Origin: Named in 1790 after the original locality in Aragon, Spain.